Apparatus for providing a representation of celestial bodies



1956 w. A. EISENHAUER 3,290,799

APPARATUS FOR PROVIDING A REPRESENTATION OF CELESTIAL BODIES Filed May 25, 1964 4 Sheets-Sheec 1 INVENTOR WILLIAM A. El SEN HAUER ATTOR EYS 1966 w. A. EISENHAUER 3,

APPARATUS FOR PROYIDING A REPRESENTATION OF CELESTIAL: BODIES 4 Sheets-Sheet 9 Filed May 25, 1964 INVENTOR.

W I LLI AM AAEI SEN HAUER Dec. 13, 1966 w. EISENHAUER 3,290,799

APPARATUS FOR PROVIDING A REPRESENTATION OF CELESTIAL BODIES 4 Sheets-Sheet 5 Filed May 25, 1964 FIGJZ.

WILLIAM A.EISENHAUER B x .2;-J;;:L

ATTORNEYS Fl r INVENTOR.

13, 1965 w. A. EISENHAUER 3,290,799

APPARATUS FOR PROVIDING A REPRESENTATION OF CELESTIAL BODIES Filed May 25, 1964 4 Sheets-Sheet INVENTOR.

W I LLIAM A .EISENHAUER ATTO RNEYS United States Patent 3,290 799 APPARATUS FOR PROVIDING A REPRESENTA- TION F CELESTIAL BODIES William A. Eisenhauer, Van Wert, Ohio, assignor to William A. Eisenhauer, Wiliiam P. Ellwood, Ida J., and Leigh Eisenhauer, doing business as The Eisenhauer Manufacturing Company, Van Wert, Ohio, co-partners Filed May 25, 1964, Ser. No. 369,958 9 Claims. (Cl. 35-44) The present application is a continuation-in-part of my prior copending application, Serial No. 271,658, filed April 9, 1963, which is a continuation-in-part of my prior application, Serial No. 851,548, filed November 9, 1959, Patent No. 3,088,228.

The present invention relates to astronomy and refers more specifically to Copernican apparatus for providing a representation of celestial bodies as they would appear at a selectable time and date, including means for directly determining the hours of right ascension of any particular celestial body and the time before the particular celestial body will be at a viewing meridian, a solar clock time dial calibrated in mean solar time and operable with a standard time equivalent dial for converting local to standard time and moon phase indicating means and method of use thereof.

With prior apparatus for indicating celestial bodies visible at a selected time and date there has been a question as to the calibration of the time scale presented thereon. Thus any of, sidereal, apparent, mean solar or local and standard time may be used to calibrate a time scale. The calibration of time scales on difierent time basis has, in the past, added considerable confusion in the study of stars.

Apparatus for viewing celestial bodies visible at a selected time and date have usually included no means by which direct conversion of local to standard time could readily be accomplished. Further, prior apparatus for viewing celestial bodies visible at a selected time and date have not provided structure for or a method of directly determining the time before a celestial body having a particular right ascension would be present at a viewing meridian. Such apparatus has also usually been substantially Ptolemaic in operation rather than Copernican and has included no moon phase or time of moon rising and setting indicia or representation of the effect of precession on the location of stars with respect to the earth. Representation of the equation of time, universal time, the planets in proper location and the sun have also been missing on many prior apparatus for viewing celestial bodies.

These deficiencies have been noted in planispheres and are particularly present in planetaria and other three dimensional starscopes since the mechanism for providing such information is more complicated in conjunction with the three dimensional representations of celestial bodies.

It is therefore one of the objects of the present invention to provide improved apparatus for viewing celestial bodies visible at a selected time and date.

Another object is to provide apparatus for viewing representations of celestial bodies visible at a selected time and date which is essentially Copernican in operation.

Another object is to provide apparatus for viewing representations of celestial bodies visible at a selected time and date including means for directly ascertaining the hours of right ascension of any celestial body.

Another object is to provide apparatus for viewing representations of celestial bodies visible at a selected time and date including means for determining the time before a celestial body will be present at a viewing meridian.

Another object is to provide apparatus for viewing representations of celestial bodies visible at a selected time and date including a mean solar time scale and means for converting local to standard time.

Another object is to provide a method of using apparatus for visually representing celestial bodies as they would appear at a selected time and date, including locating a celestial .body in accordance with the right ascension of the celestial body and directly determining the time before the celestial body will be present at a viewing meridian.

Another object is to provide apparatus for viewing representations of celestial bodies visible at a selected time and date including 'a mask and horizon control member having oppositely positioned view and sun arrows indicated thereon, a date dial including a right ascension scale thereon and a time dial including a solar clock scale calibrated in mean solar time and a different hour dial.

Another object is to provide apparatus for viewing representations of celestial bodies as set forth above and further including a sight window in the mask and horizon control member for viewing aligned portions of the date dial and time dials.

Another object is to provide apparatus for viewing representations of celestial bodies as set forth above which further includes a standard time equivalent dial operably associated with the time ,dial for converting local time to standard .time.

Another object is to provide apparatus for viewing representations of celestial bodies as set forth above which further includes moon phase indicating indicia.

Another object is to provide apparatus for viewing representations of celestial bodies as set forth above which further includes indicia indicating the path of the Earths pole and change in star positions relative to an Earth location due to precession of the Earth.

Another object is to provide a Copernican method of using apparatus for viewing celestial bodies as set forth above including first setting the mask and horizon control member so that the sun arrow .points to a selected date on the date dial, setting the time :dial so that midnight on the solar clock scale is aligned with the viewing arrow on the mask and horizon control member and subsequently moving the maskand horizon control member so that the view arrow points to the desired hour on the solar clock scale at which it is desired to view the celestial bodies.

Another object is to provide a method of using apparatus for viewing representations of celestial bodies as set forth above comprising, locating ,a particular represented celestial body by reference to the hours of right ascension scale, setting the zero .hour on the time scale of the differential hour dial radially in line with the representation ,of the particular celestial body and reading the time before the particular celestial body will be present at the viewing meridian from the :time scale on the differential hour dial opposite the view arrow on the maskand horizon control member.

Another object is to provide planisphere structure including the features set forth above.

Another object is to provide planetaria structure including the features set forth above.

Another object is to provide starscope structure including the features set forth above in which all of the celestial bodies are represented on a spherical segment and the celestial bodies are viewed through a sight opening in a body member secured thereto.

Another object is to provide structure as set forth above wherein the body member is in the form of a truncated cone and the sight opening through which the celestial bodies are viewed which is in the small end thereof and is oriented to a forty degree North latitude position.

Another object is to provide apparatus for viewing the celestial bodies as they would appear at a selected time and date and method of use thereof which are simple, economical and efficient.

Other objects and features of the invention will become apparent as the description proceeds, especially when taken in conjunction with the accompanying drawings, illustrating a preferred embodiment of the invention, wherein:

FIGURE 1 is a partial plan view of a planisphere con structed in accordance with the invention including a mask and horizon control member, a date dial having a scale providing hours of right ascension, a time dial having a solar clock scale calibrated in mean solar time, a standard time equivalent dial, a second date dial, a differential hour dial and moon phase, precession and equation of time indicia as Well as indicia to aid in locating Venus and Mercury.

FIGURE 2 is a partial elevation view of the planisphere illustrated in FIGURE 1 taken in the direction of arrow 2 in FIGURE 1.

FIGURE 3 is an elevation view partly broken away of a planetarium constructed in accordance with the invention and including dials and scales equivalent to many of the dials and scales of 'the planisphere illustrated in FIGURES l and 2.

FIGURE 4 is a bottom view of the planetarium illustrated in FIGURE 3 taken in the direction of arrow 4 in FIGURE 3.

FIGURE 5 is an enlarged section view of a portion of the planetarium illustrated in FIGURE 3 taken substantially on the line 5-5 in FIGURE 3.

FIGURE 6 is an enlarged section view of another portion of the planetarium illustrated in FIGURE 3 taken substantially on the line 66 in FIGURE 3.

FIGURE 7 is a partially broken away elevation view of a starscope constructed in accordance with the invention and including dials and scales equivalent to many of the dials and scales of the planisphere illustrated in FIGURES 1 and 2.

FIGURE 8 is an enlarged section view of the starscope illustrated in FIGURE 7 taken substantially on the line 88 in FIGURE 7.

FIGURE 9 is an enlarged section view of the spherical segment of the starscope illustrated in FIGURE 7 taken substantially on the line 99 in FIGURE 7 and showing the hours of right ascension scale on the spherical segment.

FIGURE 10 is an enlarged section view of a portion of the starscope illustrated in FIGURE 7 taken substantially on the line 10-10 in FIGURE 8.

FIGURE 11 is an end view of the starscope illustrated in FIGURE 7 taken in the direction of the arrow 11 in FIGURE 7.

FIGURE 12 is an elevation view of a modification of the starscope illustrated in FIGURE 7 showing the sight opening oriented at a forty degree North latitude position.

With particular reference to the figures of the drawings, one embodiment of the present invention will now be considered in detail.

Planisphere 10 includes a date dial 14 having a date scale 19 and right ascension scale 21 calibrated in degrees and hours of right ascension thereon surrounding centrally located star indicia 27, a further date dial 41 with date scale 43 and an outer differential hour dial 16 having differential hour'and azimuth and degree angle scales 23 and 25 around the outer periphery thereof. The ecliptic 29, equator 31 and circular path 33 of the Earths axis and relative displacement of the Earth and stars due to precession are indicated on date dial 14 along with the star indicia 27.

The planisphere 10 shown in FIGURE 1 further includes a solar clock dial 12 having scale 11 calibrated in mean solar time and moon phase and time of moon rising and setting indicia 13 thereon and a standard time equivalent dial 15 having a standard time scale 17.

The planisphere 10 is completed with the mask and horizon control member 24 for masking from view those stars not visible at a selected time on a predetermined date. Mask 24 besides being provided with sun and view arrows 30 and 32 respectively is provided with the horizon opening 28 and the radial extension 35 for encouraging Copernican operation of the planisphere having sight window 37, with indicator 39 extending radially thereacross, formed therein.

In use a direct time conversion may be accomplished between local time and the standard time by initial setting of time dials 12 and 15. Further the right ascension of any celestial body may be directly determined from the right ascension scale 21, or conversely the angular location of a celestial body is readily determined directly from the scale 21 if the hour of right ascension thereof is known.

Also, on setting of the zero hour indication of the differential hour scale 23 radially in line with a celestial body indicated on the planisphere the time before or after the appearance of the celestial body at the viewing meridian will be given directly from the differential hour scale 23 opposite the view arrow 32 on the mask 24. Scale 23 has two sets of indicia to indicate time before or after appearance of a celestial body at the viewing meridian within twelve hours either way.

Further with reference to a calendar or other media having moon phases indicated thereon and the moon phase indicia 13 on the solar clock dial 12 the moon phase and approximate time of rising and setting of the moon for a predetermined day may be determined.

Also, the effect of precession on the relative position of a point on the earth and stars may be made on viewing the ecliptic and equator indicia 31 and 33 with respect to the original and present position of the first point of Aries as illustrated in FIGURE 1.

More specifically the planisphere 10 includes five separate flat circular dials 16, 41, 15, 12 and 14 which are progressively smaller in diameter and which are concentrically mounted in the named order for relative rotation on the mounting pin 26. Each of the dials 16, 41, 15, 12 and 14 are separately rotatable and contain different scales and indications thereon. In addition a mask and horizon control member 24 having radial extension 35 depending from a circular portion smaller than dial 14 and concentric therewith is mounted for rotation on pin 26 over dial 14.

The mask and horizon control member 24 includes the elliptical opening 28 therein which is a representation of the horizon of a viewer of a celestial sphere which sphere is represented by the star indicia 27 on date dial 14 positioned immediately below the mask and horizon control member 24. The polar axis of the celestial sphere represented on date dial 14 is at the pin 26 and the viewing latitude of an observed looking at the celestial sphere is forty degrees North latitude.

Radial extension 35 on the mask and horizon control member 24 provides a handle for movement of the mask and horizon control member 24 relative to the star indicia 27. Thus operation of the planisphere 10 is essentially Copernican as the horizon moves relative to the stationary stars as will be seen in more detail subsequently. Sight opening 37 is provided in extension 35 to permit viewing of related sidereal, local and standard times as well as differential hour angle and date in one place with the aid of the indicator 39.

There are also provided on the mask and horizon control member 24 the oppositely pointing 'and oriented sun arrow 30 and view arrow 32, previously referred to, the purpose of which will become clear subsequently.

In addition a time scale 45 similar to mean solar time scale 11 but extending counterclockwise around the outer periphery of the circular portion of the mask and horizon control has been provided and may be used in direct setting of the planisphere to a selected time on a predetermined date. However, such direct setting tends to be Ptolemaic rather than Copernican in nature and is therefore not recommended. The scale 45 is essentially intended to be used as a Copernican counterpart for locating the sun, moon phases and eventhe morning and evening stars as it operates as a moving dial as the horizon control member 24 is moved. Thus scale 45 and the concentric degree scale 47 also on the periphery of the mask and horizon control provide an indication of the hours and degrees of movement of the sun and other heavenly bodies during a day.

The date dial 14, in addition to having representations 27 of celestial bodies thereon which include all of the celestial bodies viewable from a forty degree North latitude viewing location and which are laid out with the pin 26 as the polar axis, is provided with a date scale 19 representing each of the calendar days of the year equally spaced therearound, the zodiac sign of the days of the year 38 and the previously indicated degree and hours of right ascension scales 21. The date scale 19, zodiac sign scale 38 and degree and hours of right ascension scales 21 are of progressively larger diameter and the date scale is of larger diameter than the peripheral diameter of the circular portion of mask and horizon control member 24, as illustrated in FIGURE 1.

Also, the path of the earths pole 33 on the celestial sphere represented as well as the projection of the equator and ecliptic are provided on dial 14 to show the relatively minor effect of precession of the earth on the right ascension and declination of the stars with relation to a position of the earths surface. The right ascension change for the first point of Aries over the last two thousand years plus is indicated along the ecliptic while the declination change is indicated between the equator and ecliptic. Thus it takes approximately twenty-six thousand years for the pole to traverse the circle 33. Corrections for precession are therefore seldom necessary.

The solar clock dial 12 includes thereon a scale 11 positioned at the radially outer periphery thereof calibrated in mean solar time and previously referred to. The scale 11 is of larger diameter than the peripheral diameter of the date dial 14.

The solar clock dial 12 as indicated above is calibrated in accordance with the mean time which is based on a circular orbit conception that averages the time over a year in daily increments of twenty-four hours rather than an apparent time scale would be based on the true sun time which is a consequence of the earth processing varying amounts of are as it moves in an ellipse about the sun during the year. Mean solar time differs from apparent solar time a maximum of about sixteen minutes in either direction as indicated at 43 on solar clock dial 12. The maximum deviation is thus a relatively insignificant amount and may be corrected for with the use of the time equation if desired.

The user of the planisphere will not have to correct for the difference between mean solar time and sidereal time asset forth on scale 21 since the difference is only a matter of about four minutes in one day and the daily adjustment which follows the alignment of the mean time dial automatically picks the daily difference between sidereal and solar mean time accumulatively.

The solar clock dial 12 is also provided with moon phase indicia 13 thereon which may be used in conjunction with a calendar or the like giving moon phase to determine the moon phase and approximate time of rising and setting of the moon on a predetermined date. Thus on a standard basis a new moon rises at 6:00 A.M., a first quarter moon rises at 12:00 noon, the full moon rises at 6:00 P.M., and the last quarter rises at 12:00 RM. The number of days past a particular phase multiplied by fifty-two will give the number of minutes to he added to the rise time of the phase to obtain the rise time of the moon on the particular day.

For example, if a new moon is indicated from a reference such as a calendar for March 14, 1964, the

phase of the moon on March 17 will be seen on dial 12 as the third moon indicia clockwise from the indicated new moon position. Also, the time of rising of the moon on March 17 will be between the 6:00 A.M. rising of the new moon and the 12:00 noon rising of the first quarter moon on March 20 or approximately 8:35 A.M. The moon phase may be positioned and timed with respect to the time of date selected with the fixed mask time scale 45.

Whenever the user may be fortunate enough or plans on exact reference of the risings of the nearest quarter instead of the rougher type approximations, then by multiplying the number of days difference by fifty-two minutes per days involved for an adjustment, then by basing the final figure on the correct base time would result in a much closer timing for the rising of the particular phase under consideration.

The relative angular positions of the morning and evening stars, Mercury and Venus, with respect to the sun are also indicated on solar clock dial 12. The exact position of Mercury and Venus will, of course, depend on the phase relation of the Earth, Mars and Venus in their orbits about the sun.

A correction may be made by the user of the planisphere 10 is desired to convert from mean solar or local time to standard time. Thus four minutes for each de ree must be added to local time to provide standard time if the observers position is west of a standard time meridian. The four minutes per degree must be subtracted from the mean solar time if the observer is east of the standard meridian. This correction can be accomplished by use of the degree scale provisions 43 at 12:00 noon on the standard time equivalent dial providing fifteen degrees of adjustment east or west.

Since this correction is always the same for a given geographical location the standard time equivalent dial 15 has been added to planisphere 10. In use the standard time equivalent dial 15 is rotated to provide the correction between standard time on scale 17 and local time on scale 11 of solar clock dial 12. The dials 15 and 12 are then locked together by convenient means (not shown). Direct conversion between local and standard time may thereafter be made for the given geographical location by observing aligned times on scales 17 and 11.

Dial 41 has date scale 43 around the outer periphery thereof and is provided to permit setting of all desired information in sight opening 37 in use of the planisphere.

The dial 16 has on its outer periphery the differential hour scale 23 previously referred to in which hours from zero to twelve hours are represented by equal divisions over one hundred eighty degrees of the periphery of the dial each way from a zero differential hour. An azimuth and degree angle scale 25 is also provided on the dial 16 radially inwardly of the differential hour scale 16. The diameter of the scale 16 is greater than the peripheral diameter of the dial 41, as illustrated in FIGURE 1.

In use the planisphere of FIGURES 1 and 2 will provide a visual representation of celestial bodies as they would appear at a selected time and date. Further, the

planisphere 10 will provide a direct indication of the time before any particular celestial body will appear at a viewing meridian as well as the information concerning the moon phases and rising and setting and precession set forth in detail above.

Since the solar clock scale 11 is calibrated in mean solar time and since conversion between local and standard time may be made directly from dials 12 and 15 as indicated above and sidereal, local and standard time are represented in the single sight opening 37 of planisphere 10, calculations with pencil and paper while using planisphere 10 to convert between the different times are reduced to a minimum.

To provide a visual representation of celestial bodies as they would appear at a selected time and date it is assumed that the selected time and date is September 25, at 2:00 in the morning. The mask and horizon control member is then first rotated so that the sun arrow 30 points at September 25 on date scale 19. The solar clock dial 12 is then rotated until the zero hour indication on the time scale 11 is opposite the view arrow 32.

Since all times available on the local mean time dial for the date selected belong to that date only, the celestial bodies 27 indicated within the opening 28 of the mask and horizon control member 24 will then be the celestial bodies visible at zero hour on September 25. The mask and horizon control member 24 is then rotated so that the view arrow 32 points to 2:00 in the morning on the time scale 11. The celestial bodies visible at 2:00 in the morning on September 25 are then visible through the opening 28 in the mask and horizon control member 24.

Before the above procedure is accomplished or during the procedure conversion between local and standard time is by direct reading between the mean solar time scale 11 and the standard time scale 17 on the dials 12 and 15 which are set for a particular locality and secured together as indicated above. Similarly at any time during the use of the planisphere the special date dial 41 may be positioned to provide the date on scale 43 at which the stars are viewed in the opening 37. Thus all the usual information required in the use of the planisphere 10 is available in the sight opening 37.

When it is desired to determine the time before which a particular celestial body will appear at the viewing meridian with the celestial body within twelve hours of appearing at the viewing meridian, the celestial body is first located in accordance with its degree and hours of right ascension by means of scale 21 on date dial 14. The outer difierential hour dial 16 is rotated until the zero hour indication on scale 23 is aligned radially through the pin 26 and the particular celestial body. The time in hours before the particular celestial body will appear at the viewing meridian will then be given on the differential hour scale 23 directly opposite the view arrow 32 on the mask and horizon control member in sight opening 37.

A similar procedure will provide a direct reading of the number of hours after the appearance of a celestial body at the viewing meridian if the celestial body has appeared at the viewing meridian within the preceding twelve hours. However, it will normally not be of great interest to determine the time after the passing of a celestial body.

The planetarium illustrated in FIGURES 36 is similar to the planetarium illustrated in FIGURES 1 and 2 of commonly owned Patent No. 3,088,228. The planetarium 42 thus includes the hemispherical members 44 and 46 connected at their flanged open sides by means of a date ring 48. Planetarium 42 further includes the mask 50 rotatably positioned within the sight opening 58 in the hemisphere 44 and held in assembly therewith by the mask and horizon control member 52. The member 52 is urged outwardly of the planetarium 42 by the spring 54 as before and the hour dial 56 is mounted on 8 the mask and horizon control member 52 for rotation with respect thereto, as shown best in FIGURE 5.

Again the celestial bodies are represented by perforations in the members 44 and 46 and are viewable through the sight opening 58. The mask 50 prevents viewing of celestial bodies which are not visible at the selected time and date. A reference meridian 60 is provided and celestial body representations 62 are supported on a wire ring 64 held in position within the planetarium 42 due to clamping of wire supports 61 for ring 64 between the hemispheres 44 and 46 by the date ring 48.

The planetarium 42 includes a time scale 68 on the hour dial 56 which is calibrated in mean solar time. Hour dial 56 differs from the hour dial in the planetarium 10 in the above referenced patent in that the outer periphery 66 thereof has been angled at substantially forty-five degrees to the time scale 68 and a differential hour scale 70 has been provided thereon.

Also, a standard time equivalent scale 71 has been provided on the annular ring 73 secured to the hour dial 56 for angular movement with respect thereto by means of slots 75 and bolts 77. Thus, again after initially setting the ring 73 for a predetermined locality direct conversion between local and standard time may be accomplished.

Moon phase indicia 79 and time of rising and setting of the quarter moon phases have also been added to the hour dial 56 as seen best in FIGURE 4.

The date ring 48 in the planetarium 42 includes thereon a date scale 72. Further an hours of right ascension scale 74 has been provided radially outwardly of the date scale 72 on the ring 48, as best shown in FIGURE 4.

Thus in use of planetarium 42 the celestial bodies visible at a particular time on a predetermined day may be viewed through the sight opening 58 on manipulation of the sun and view arrows 55 and 57 respectively on mask and horizon control member 52 and the hour dial 56 with reference to the date scale 72 on date ring 48 in accordance with the procedure set forth in the above referenced patent.

When it is desired to determine the time before a predetermined celestial body will be present at the viewing meridian, the celestial body is located by reference to the hours of right ascension scale 74 on date ring 48. The hour dial is then turned so that the zero hour indication on the differential hour scale 70 is directly radially outward of the celestial body. The time before which the celestial body will be at the viewing meridian will then be indicated on the differential hour scale 70 of the hour dial 56 directly opposite the view arrow 57 on the mask and horizon control member 52.

The starscope 76 for viewing a representation of celestial bodies as they would appear at a selected time and date illustrated in FIGURES 7-11 is similar to the starscope 60 disclosed in commonly owned, copending patent application, Serial No. 271,658.

Thus the starscope 76 comprises a spherical segment 78 in which perforations are provided in the position of and representing celestial bodies 82 on that portion of a celestial sphere viewable from a selected latitude, for example forty degrees North latitude. The spherical segment 78 has on the interior thereof adjacent the outer periphery an annular hours of right ascension scale 81 whereby the hours of right ascension of particular celestial bodies may be readily determined during viewing.

The starscope 76 further includes the mask for masking the celestial bodies 82 represented on the spherical segment 78 which are not visible at a selected time on a selected date from view through the sight opening 84.

The starscope 76 further includes the time dial 86 having a solar clock scale 92 thereon calibrated in terms of mean solar time, a standard time equivalent scale 87 on annular ring 89, a date dial 88, and a mask and horizon control dial 90.

The solar clock scale 92 on time dial 86 is positioned radially outwardly of the date dial 88 and is mounted for concentric rotation on the date dial 88 by the open returnedouter periphery 94 of the annular time dial mounting ring 96. The annular ring 89 is adjustably mounted to permit relative angular rotation between scales 92 and 87 by means of slots 91 and bolt and nut locking devices 93.

As will be understood from the foregoing, moon phase indicia and time of rise and set of the moon in the different phases thereof could be provided on a radially extended time dial if desired in the manner indicated in conjunction with the planisphere and the planetarium 42.

The date dial 88 has separate date of the year and hours of right ascension scales 98 and 100 thereon, as best shown in FIGURE 8, and is fixedly secured to the outer periphery of the flange 102 of the spherical segment 78. In addition the date dial 88 and therefore the spherical segment 78 is mounted for rotation on the mask and horizon control dial 90 by means of the open returned: outer periphery 104 of the annular date dial mounting ring 106.

The mask and horizon control dial 90 is fixedly secured to the larger end 108 of the body member 110 of the starscope 76 by convenient means, such as the annular mounting ring 112, as illustrated best in FIG- URE 11.

The body member 110 of the starscope 76 is in the form of a truncated cone, the larger end 108 of which is connected to the mask and horizon control dial 90, as indicated above, and the smaller end 114 of which is connected to a sighting ring 116, as shown best in FIGURE 7. The sighting ring 116 includes the sight opening 84 .through which the celestial bodies on the spherical segment 78 are viewed and includes the indications of the major points of the compass around the periphery thereof, as indicated in FIGURE 11.

Thus in use when it is desired to view the celestial bodies visible at a selected time on a selected date, with the starscope 76, the sun arrow 118 on the mask and horizon control dial 90 is positioned opposite the selected date on the date dial 88. The time dial 86 is then rotated until midnight on the solar clock scale 92 is opposite the view arrow 120 on the mask and horizon control dial 90. As before the celestial bodies viewable through the sight opening 84 and the mask 80 at this time are those viewable at zero hour on the selected day.

The mask and horizon control dial 90 is then rotated relative to the time dial 86 and the date dial 88 until the view arrow 120 points to the selected time on the solar clock scale 92. The celestial bodies represented on the spherical segment 78 viewed from the sight opening 84 through mask 80 will then be the celestial bodies visible at the selected time on the selected date.

It will be obvious that by adding a differential hour dial as in the case of the planisphere 10 and the planetarium 42 that a direct reading of the time before a predetermined celestial body would appear on the viewing meridian could be obtained with the starscope structure 76. The differential hour dial could be added radially outwardly of the sight opening 84 for angular rotation with respect to dial 86.

Further as set forth in the above referenced co-pending patent application the body member 110 of the starscope 76 may be altered in shape. Additionally the sight opening 84 may be oriented for the particular viewing latitude. Thus, as shown in FIGURE 12, the sight opening 122 is oriented at forty degrees North latitude and the body member 124 is considerably shortened.

While one embodiment of the present invention and modifications thereof have been considered in detail, other embodiments, and modifications are contemplated. For example, it would be possible to alter the mask and horizon control member 24 to provide a view of all stars visithereon to indicate the limit of viewing from specific f latitudes such as the forty degree latitude to which the mask and horizon control member 24, as shown in FIGURE 1, is now limited. It is the intention to include all embodiments and modifications as are defined by the appended claims within the scope of the invention.

What I claim as my invention is:

1. A planisphere for providing a representation of celestial bodies visible at a selected time on a selected date comprising a plurality of concentric dials, a central pin to which the concentric dials are secured and about which the concentric dials are separately rotatable, the first radially smaller of the dials being a mask and horizon control dial including an elliptical portion through which the second dial is viewable representing the horizon of an observer at a predetermined latitude, the rest of the first dial acting as a mask to mask from view representations of celestial bodies not visible at a selected time on a selected day which are represented on the sec-0nd dial and having oppositely positioned view and sun arrow indications thereon, the sec-0nd dial being radially larger than the first dial and in surface-to-surface contact therewith and including thereon a planar representation of the celestial bodies visible from the predetermined latitude with the pivot pin as the polar axis, said second dial including around the periphery thereof a date scale and a degree and hours of right ascension scale, a third dial being radially larger than the second dial and positioned in surface-to-surface contact with the second dial on the opposite side thereof from the first dial and including a solar clock scale around the outer periphery thereof and means connected to the planisphere for directly determining the time before a particular celestial body represented on the second dial will be present at a viewing meridian.

2. Structure as set forth in claim 1 wherein the means for directly determining the time before a particular celestial body will be at a viewing meridian comprises a fourth dial on the opposite side of the third dial from the second dial which fourth dial is larger in diameter than the third dial and is mounted for rotation about its center on the pivot pin and includes on the outer periphery thereof a differential hour scale and an azimuth and degree angle scale.

3. Structure as set forth in claim 1 wherein the solar clock scale on the third dial is calibrated in terms of mean solar time.

4. Structure as set forth in claim 1 and further including means connected to the planisphere for directly converting between local time and standard time including a fourth dial concentric with the third dial and mounted for rotation on the pivot pin having a standard time equivalent scale on the periphery thereof adjacent the solar clock scale.

5. Structure as set forth in claim 1 and further including means on the third dial for indicating moon phases and the approximate time of rising and setting of the moon.

6. Structure as set forth in claim 1 and further including a radial projection on the first dial having a viewing window extending theret'hrough for viewing portions of the other dials radially aligned with the view arrow and for facilitating moving of the first dial relative to a stationary second dial whereby operation of the planisphere is essentially Copernican.

7. Structure as set forth in claim 1 and further including a degree scale on the fourth dial for facilitating the positioning of third and fourth dials to permit direct conversion between local time and standard time.

8. Structure as set forth in claim 7 wherein the means for indicating the correction of the time equation com- 1 1 1 2 prises a scale on the third dial indicating sixteen minutes 2,532,324 12/1950 Milligan. on each side of a noon indication. 2,755,565 7/1956 Alkerna 3544 9. Structure as set forth in claim 1 and further includ- 2,907,584 10/ 1959 Neilsen 28115 ing means secured to the second dial around the periphery 2,921,386 l/1960 Stefano 3544 thereof representative of the location of the planets 0n 5 3,088,228 5/1963 Eisenhauer 3545 le dates- FOREIGN PATENTS References Cited by the Examiner 882,320 7/ 1953 Germany.

UNITED STATES PATENTS l0 JEROME SCHNALL, Primary Examiner.

Barrltt R Exam ne 1,153,492 9/1915 Hoitinga 58-3 2,478,981 8/ 1949 Randall 3544 S. S. KOGQUIST, Assistant Examiner. 

1. A PLANISPHERE FOR PROVIDING A REPRESENTATION OF CELESTIAL BODIES VISIBLE AT A SELECTED TIME ON A SELECTED DATE COMPRISING A PLURALITY OF CONCENTRIC DIALS, A CENTRAL PIN TO WHICH THE CONCENTRIC DIALS ARE SEPARATELY ROTATABLE, THE WHICH THE CONCENTRIC DIALS ARE SEPARATELY ROTATABLE, THE FIRST RADIALLY SMALLER OF THE DIALS BEING MASK AND HORIZON CONTROL DIAL INCLUDING AN ELLIPTICAL PORTION THROUGH WHICH THE SECOND DIAL IS VIEWABLE REPRESENTING THE HORIZON OF AN OBSERVER AT A PREDETERMINED LATITUDE, THE REST OF THE FIRST DIAL ACTING AS A MASK FROM VIEW REPRESENTATIONS OF CELESTIAL BODIES NOT VISIBLE AT A SELECTED TIME ON A SELECTED DAY WHICH ARE REPRESENTED ON THE SECOND DIAL AND HAVING OPPOSITELY POSITIONED VIEW AND SUN ARROW INDICATIONS THEREON, THE SECOND DIAL BEING RADIALLY LARGER THAN THE FIRST DIAL AND IN SURFACE-TO-SURFACE CONTACT THEREWITH AND INCLUDING THEREON A PLANAR REPRESENTATION OF THE CELESTAIL BODIES VISIBLE FROM THE PREDETERMINED LATITUDE WITH THE PIVOT PIN AS THE POLAR AXIS, SAID SECOND DIAL INCLUDING AROUND THE PERIPHERY THEREOF A DATE SCALE AND A DEGREE AND HOURS OF FIGHT ASCENSION SCALE, A THIRD DIAL BEING RADIALLY LARGER THAN THE SECOND DIAL AND POSITIONED IN SURFACE-TO-SURFACE CONTACT WITH THE SECOND DIAL ON THE OPPOSITE SIDE THEREOF FROM THE FIRST DIAL AND INCLUDING A SOLAR CLOCK SCALE AROUND THE OUTER PERIPHERY THEREOF AND MEANS CONNECTED TO THE PLANISPHERE FOR DIRECTLY DETERMINING THE TIME BEFORE A PARTICULAR CELESTIAL BODY REPRESENTED ON THE SECOND DIAL WILL BE PRESENT AT A VIEWING MERIDIAN. 